Increase window-size for headless features tests

:selenium_chrome_headless driver has a default window-size of (800x600). This small window-size seems to result in the `Selenium::WebDriver::Error::ElementClickInterceptedError:`

This commit increases the window-size and also reverts the prior fix for these errors (commit 55321d0)

spec/features/super_admins/merge_org_spec.rb

@@ -45,16 +45,7 @@
     expect(page).to have_text('Merge Organisations')
     choose_suggestion('org_org_name', @to_org)
 
-    # rubocop:disable Layout/LineLength
-    # Using JS to click on button as click_button 'Analyze' fails due to error like
-    # Selenium::WebDriver::Error::ElementClickInterceptedError: element click intercepted:
-    # Element <button name="button" type="submit" class="btn btn-primary">...</button> is not clickable at point (86, 349).
-    # Other element would receive the click: <div id="ui-id-2" tabindex="-1" class="ui-menu-item-wrapper">...</div>
-    # So replacing  click_button 'Analyze'with
-    # rubocop:enable Layout/LineLength
-    analyze_button = find('button', text: 'Analyze')
-    execute_script('arguments[0].click();', analyze_button)
-
+    click_button 'Analyze'
     # Wait for response
     sleep(0.3)
     expect(page).to have_text('Summary:')

spec/features/templates/templates_upgrade_customisations_spec.rb

@@ -52,16 +52,7 @@
 
     # Move to the other funder Org's Templates
     choose_suggestion('superadmin_user_org_name', funder)
-
-    # rubocop:disable Layout/LineLength
-    # Using JS to click as click_button "Change affiliation" fails due to error like
-    # Selenium::WebDriver::Error::ElementClickInterceptedError: element click intercepted:
-    # Element <input type="submit" name="commit" value="Change affiliation" class="btn btn-secondary" data-disable-with="Change affiliation">
-    # is not clickable at point (101, 203). Other element would receive the click: <div id="ui-id-2" tabindex="-1" class="ui-menu-item-wrapper">...</div>
-    # So replacing click_button('Change affiliation')
-    # rubocop:enable Layout/LineLength
-    change_affiliation_input_button = find('input[value="Change affiliation"]')
-    execute_script('arguments[0].click();', change_affiliation_input_button)
+    click_button('Change affiliation')
 
     # Edit the original Template
     click_link "#{funder.name} Templates"

spec/support/capybara.rb

@@ -6,13 +6,23 @@
 # Use the fast rack_test driver for non-feature tests by default
 Capybara.default_driver = :rack_test
 
+# Create a custom driver based on Capybara's :selenium_chrome_headless driver
+# This resolves a ElementClickInterceptedError when executing `click_button 'Sign in'` with DMP Assistant
+Capybara.register_driver :selenium_chrome_headless_add_window_size do |app|
+  # Get a copy of the default options for Capybara's :selenium_chrome_headless driver
+  options = Capybara.drivers[:selenium_chrome_headless].call.options[:options].dup
+  options.add_argument('--window-size=1920,1080') # default window-size is only (800x600)
+  # Create a new Selenium driver with the customised options
+  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
+end
+
 RSpec.configure do |config|
   config.before(:each, type: :feature, js: false) do
     Capybara.use_default_driver
   end
 
   # Use the Selenium headless Chrome driver for feature tests
   config.before(:each, type: :feature, js: true) do
-    Capybara.current_driver = :selenium_chrome_headless
+    Capybara.current_driver = :selenium_chrome_headless_add_window_size
   end
 end